There are plenty of extraordinarily qualified sources already refuting the spread of the flat earth belief - the problem is not one of adequate fact checking. These are people that want to believe the earth is flat, you are unlikely to convince them otherwise by dinging YouTubers who specialize in such videos, and most attempts to convince them via argument are met with some sort of pseudo-scientific technobabble or increased conspiracy fueled paranoia.

Some number of people are functionally crazy, easier to just calmly refute their psychosis with actual science and fact via multiple channels... which is how this is handled in thousands of books, on hundreds of YouTube channels, and in dozens of podcasts.

Yet again - logical argument doesn't even dent illogical beliefs which some people are emotionally invested in.

[link]https://wiki.tfes.org/Planets[/link]
'Rotundity
Q. If the planets are round, why isn't the earth?
A. The earth is not a planet. '
I've been reading their site. They have answers for most things, including little rotating models showing the the passage of the sun. I am beginning to doubt my sanity.....

And yet, thanks to an immeasurably flawed conspiracy theory, a small but dedicated group of people is still convinced that Earth is flat. One of these so-called Flat Earthers is a guy named "Mad" Mike Hughes, and Hughes—a 61-year-old limo driver—has spent the past few years building a homemade, steam-powered rocket in his garage to prove he's right."

"I don’t believe in science," Hughes told the AP. "I know about aerodynamics and fluid dynamics and how things move through the air, about the certain size of rocket nozzles, and thrust. But that’s not science, that’s just a formula. There’s no difference between science and science fiction."

'If you’re in a helicopter and you hover, why does the Earth not come to you if it’s round?'

You can sort of understand why people might think 911 is dodgy and even how some might think there is something sinister about chemtrails but this flat Earth stuff is just too nonsensical - no-one can be that stupid.

I think Tony's 'Joke that got out of hand' comment is apposite - we are being wound up.

"A California man who planned to launch himself 1,800 feet high Saturday in a homemade scrap-metal rocket — in an effort to prove that Earth is flat — said he is postponing the experiment after he couldn't get permission from a federal agency to conduct it on public land."